I have a poly blank with 1/4" basswood stringer. It’s a U.S. Blank blue foam 9-3 Y. Noticed before I started that it had a gnarley twist. Cut out my shape and tried to plane off an extra 1/8" on one half of bottom side, but could see that wasn’t going to work. Right now it’s sitting on my racks with weights on each end on diagonals. Bottom is skinned but top is untouched.
Any suggestions on how to fix this? Maybe a week with the weights on? I have another blank I could get started on while this one is de-twisted. Thought I could shape the twist out but I have my doubts.
Twisted is twisted, doubt it will fix itself or with your weight system. Probably end up with a thinner board than desired, but it’s worth a go, too late since you already started in on it. Personally, after shaping a 12’3" Clark single stringer, (half-inch), a couple of years ago, I wouldn’t want to tackle it. Being that it’s only 9’ it might be a lot easier, it’s just so mind bending dealing with the twist, it’s hard to get it where you want it to go. I kept my 12’er, it rides fine, but I have to look at it too.
Snap a line on the deck, see what you’ve got, and go for it. Have fun. Next time, I’ll bet you’ll send it back.
Reckon just about anything can be “fixed”, but it depends on how much time and effort is worth it. I repaired a similar problem recently. Ripped the blank from one end to the other on the band saw down each side of the stringer, added two new stringers with a 1 1/4" foam piece dividing the two to make a big double T-band stringer. Then joined and trued up the sides of the blank and glued it all back together resulting in a wider but more true blank. Use winding sticks to plane it all back nice and true again.
winding sticks: Get two pieces of wood apx. 30" long x 1 1/2" wide x 3/4" thick (any sticks close to these dimensions are fine so long as they are straight). Place one of the sticks across the blank at about 18" from the tip of the nose and lay the other stick across the blank at about the same distance up from the tail. From one end of the blank, squat down eye level to the sticks and sight down the blank. The blank is true when the two sticks sight across parallel to each other.
OR, make a smaller board and get a new blank. Your call depending on the effort you wish to make, but it likely can be fixed. As previously said, bending dry foam isn’t going to work
You can spring the tweak out of it. I had a 10’7"H that I got from South Coast and it was twisted beyond shapibilty. I stuck the nose of it into a pallet to anchor it and used a cement block and fulcrum to estimate how much and how long it would take to bring it back. When it had returned to “normal”, I left it for a day longer, so it could spring baack if that was going to happen. It stayed and I shaped it and now it is in Japan, being ridden by a happy customer.
seriously, take the blank back to wherever you bought it, this kind of thing happens to me all the time. espeically with the newer green foam blanks- i just take it back and US blanks will comp you.
if you’re gonna hit the twisted or bent blank, just redraw a straight stringer line top and bottom and work off that.